Since the end of the Cold War, the number of books and articles on intervention in world politics has grown dramatically. Yet curiously little of this work subjects the concept of intervention itself to critical scrutiny. Scholars often preface their analyses with definitional discussions about what intervention is, but these definitions take a common form, conceiving intervention within a ‘sovereignty frame’. This article questions this conception of intervention, arguing that it distorts our understanding of interventionary practices and forms of reasoning that occurred in non-sovereign international orders. After exploring the sovereignty framing of intervention in greater detail, I advance an alternative conception. International orders are systemic configurations of political authority: they comprise multiple units of such authority, each with its own realm of jurisdiction, organised according to some principle of differentiation. Importantly, this principle need not be territorial: it could be functional, for example. International intervention is the transgression of a unit's realm of jurisdiction, conducted by other units in the system. Unlike the sovereign framing of intervention, this conception is equally applicable to the interventionary ideas and practices of diverse international orders, and provides a better basis on which to understand how thinkers in different historical contexts have reasoned about intervention.